Abstract
Adhesive strength of 4-META/MMA-TTB resin to fresh bovine dentin cleaned by a 10% citric acid-3% ferric chloride solution for 30 sec was 18MPa, on the other hand it decreased to 6MPa when the adhesion was carried out to the dentin etched with a 65% phosphoric acid solution for 30 sec.The strength to the phosphoric acid etched dentin which had been soaked in a 25% glutaraldehyde solution for 10 min increased to 11MPa.But it became lower to 6MPa when the aldehyde soaked dentin was cleaned by a 10% citric acid-3% ferric chloride solution.These results strongly suggest that structure of the collagen plays important role in the adhesion to dentin.The collagen crosslinked by glutaraldehyde has better resistance against the sturctural change during the acid etching.The 10% citric acid-3% ferric chloride solution is not strong enough to remove the smear layer and ingredients in the tubules which had been crosslinked by the aldehyde.The SEM observations suggested that the former 6MPa was due to the interlocking at the tubules but the latter 6MPa was due to the infiltration of monomers into peritubular dentin and intertubular dentin and not to the mechanical interlocking as previously reported.
